1. Technical Field
The present invention relates to technical fields of a photoelectric conversion element such as a PIN diode, a photoelectric conversion device including the photoelectric conversion element, and an image sensor including the photoelectric conversion device.
2. Related Art
As an example of a sensor of such a type, an image sensor that is driven as an active matrix type has been disclosed (for example, see JP-A-11-121731). In the above-described image sensor, a PIN diode that is formed by laminating a p-type semiconductor layer (p layer), a light receiving layer (i layer) that is formed of an amorphous semiconductor layer, and an n-type semiconductor layer (n layer) together is used as a photoelectric conversion element.
Here, in order to improve the detection capability for detecting a detection target, there has been a request to improve the sensitivity for detecting infrared rays. However, in a photoelectric conversion element such as a PIN diode that is used in an image sensor of such a type, there is a trade-off relationship between the increase in the sensitivity for infrared rays and the detection of minute amounts of light. Accordingly, it is technically difficult to combine an increasing sensitivity for infrared rays and detecting minute amounts of light. In addition, it is difficult to increase the detection capability of the image sensor up to the wavelength range of infrared rays.